Android Application Architecture

When you create an android project, the tool automatically creates many folders, the following explains the functions of these folders: src/Java original code storage directory GEN/Automatic Generation directory Gen directory stores all files automatically generated by Android development tools. The most important part in the directory is the R. Java file. This file is automatically generated by the android development tool. The android development tool automatically updates and modifies the R. Java File Based on the XML interface files, icons, and constants in the res directory. Because the R. Java file is automatically generated by the development tool, we should avoid manual modification to R. java. R. Java plays a dictionary role in the application. It contains the IDs of various resources such as interfaces, icons, and constants. Through R. Java, the application can easily find the corresponding resources. In addition, the compiler checks the R. whether the resources in the Java list are used, and those that are not used are not compiled into the software. This can reduce the space occupied by applications on mobile phones. The res/Resource Directory stores various resources used by applications, such as XML interface files, images, and data. For details, see the remarks column below the PPT. Androidmanifest. the XML function list file lists the functions provided by the application. In this file, you can specify services used by applications (such as telephone services, Internet services, SMS services, and GPS services ). In addition, when you add an activity, you also need to configure it in the file. The activity can be called only after the activity is configured. Default. properties project environment information, which generally does not need to be modified